Electronic circuit design often requires the use of various interface circuitries such as capacitive sensor arrays that enable the user to interact with or receive information from an electronic circuit. Typically, dedicated sensing circuitry may be used to detect the activation of various capacitive switches within a capacitive sensor array enabling a user to input particular information into a circuit.
Within a capacitive sensor array there is needed the ability to detect differences in the capacitance value of a capacitive switch responsive to the placement of a user's finger upon the capacitive switch. In addition to detecting the placement of a finger upon a capacitive switch and the associated change in capacitance caused by the finger, there is the need to make the sensing circuitry resistant to external interferences within the capacitive sensor array. Examples of external interferences include cell phones whose transmissions may cause inadvertent detection of increases of capacitance upon the switch. Additionally, electrical main circuits such as those associated with air conditioning or other high use electrical energy units can cause interference within capacitive sensor arrays. Other types of interferences and inaccuracies within the capacitive sensing circuitries may also lend themselves to errors in detection of particular capacitance values within capacitive sensor array circuitry. Thus, there is a need for providing capacitive touch sensor circuitry that enables the detection of a finger upon a capacitive sensor array while limiting the amount of detections based upon external interferences and inaccuracies and interferences inherent within the detection circuitries.